Scavenging of atmospheric ions and aerosols by drifting snow in Antarctica

Measurements of the small-, intermediate-, and large-ion concentrations and the air–earth current density along with simultaneous measurements of the concentration and size distribution of aerosol particles in the size ranges 4.4–163 nm and 0.5–20 μm diameter are reported for a drifting snow period after the occurrence of a blizzard at a coastal station, Maitri, Antarctica. Ion concentrations of all categories and the air–earth current simultaneously decrease by approximately an order of magnitude as the wind speed increases from 5 to 10 ms^− 1. The rate of decrease is the highest for large ions, lowest for small ions and in-between the two for intermediate ions. Total aerosol number concentration decreases in the 4.4–163 nm size range but increases in the 0.5–20 μm size range with wind speed. The size distribution of the nanometer particles shows a dominant maximum at ~ 30 nm diameter throughout the period of observations and the height of the maximum decreases with wind speed. However, larger particles show a maximum at ~ 0.7 μm diameter but the height of the maximum increases with increasing wind speed. The results are explained in terms of scavenging of atmospheric ions and aerosols by the drifting snow particles.     

北京冬季雾霾事件的气象特征分析

利用观测的气象要素和细颗粒物(即PM2.5)浓度资料,并结合中尺度数值天气模式WRF(Weather Research and Forecasting Model),对2013年1月北京地区雾霾污染期间天气条件和边界层气象特征进行了分析。模拟与观测对比表明,WRF模式可以较好地反映北京—天津—河北地区地面和高空主要气象要素的时空分布。对1月10~14日、27~31日两次重雾霾天气的分析表明,雾霾的形成是高浓度的大气颗粒物和特殊的气象条件共同作用的结果。小风或静风、稳定的大气层结,使大气扩散能力减弱,造成污染物堆积,偏南气流将周边污染物和水汽输送到北京,不仅增加了污染物浓度,而且有利于气溶胶吸湿增长,消光增强,使能见度下降,进而形成雾霾。     

Study of small ions concentration in the air above Athens, Greece

Measurements of positive and negative small atmospheric ion concentrations have been made regularly since 1968 at the National Observatory of Athens (NOA). In this paper the 17-year period 1968–1984 is summarized. The diurnal and annual variations are examined, and Fourier analysis is also used for the study of the diurnal variation. The concentrations of small ions follow a double diurnal course. The maxima occur near 3–5 h and 13–16 h local time (LT = GMT + 2 h). The minima are observed at 6–8 h and 21–23 h. The annual course of small ions presents maximum concentration values around the summer season. The mean of the small ion concentration (SIC) for the 17-year period (1968–1984) is n₊ = 188.8 ions/cm³ for positive ions and n₋ = 151.1 ions/cm³ for negative ions. Their ratio is equal to 1.25. The year-to-year variation of SIC for the examined period shows a negative trend. The results from multiple regression analysis show that wind speed and SIC are positively correlated, while relative humidity, smoke and sulphur dioxide are negatively correlated.     

Characteristic features of air ions at Mace Head on the west coast of Ireland

Coastal nucleation events and behavior of cluster ions were characterized through the measurements of air ion mobility distributions at the Mace Head research station on the west coast of Ireland in 2006. We measured concentrations of cluster ions and charged aerosol particles in the size range of 0.34–40 nm. These measurements allow us to characterize freshly nucleated charged particles with diameters smaller than 3 nm. The analysis shows that bursts of intermediate ions (1.6–7 nm) are a frequent phenomenon in the marine coastal environment. Intermediate ion concentrations were generally close to zero, but during some nucleation episodes the concentrations increased to several hundreds per cm³. Nucleation events occurred during most of the measurement days. We classified all days into one of seven classes according to the occurrence and type of new particle formation. Nucleation events were observed during 207 days in 2006, most prominently in the spring and summer months. Rain-induced events, in turn, were observed during 132 days. Particle formation and growth events mostly coincided with the presence of low tide. Also small cluster ions (0.34–1.6 nm) were characterized. Average concentrations of small ions were 440 cm^− 3 for the negative ions and 423 cm^− 3 for the positive ions. Average mean mobilities of small ions were 1.86 cm²V^− 1s^− 1 and 1.49 cm²V^− 1s^− 1 for the negative and positive polarities, respectively. Concentrations of small ions were observed to be strongly dependent on the variations of meteorological parameters including wind speed and direction.     

Chemical and strontium isotope characterization of rainwater at an urban site in Loess Plateau, Northwest China

Major ion concentrations and strontium isotopic ratios (⁸⁷Sr/⁸⁶Sr) were measured in rainwater samples collected at the urban site of Lanzhou, a city located on the Loess Plateau in the arid and semi-arid areas of northwest China. The rainwater samples possessed alkaline pH, at a reference level of 5.6, with a range of 6.82 to 8.28 and a volume-weighted mean (VWM) pH value of 7.70. The alkaline character of rainwater in Lanzhou is due to the result of neutralization caused by the alkaline soil dusts which contain large amount of CaCO₃. It was observed that Ca²⁺ was the most abundant cation with a VWM value of 886 µeq l^− 1 (115–2184 µeq l^− 1), accounting for 87.8% of the total cations. Without considering HCO₃⁻, SO₄²⁻ and NO₃⁻ were dominant among the anions, accounting for 64.2% and 23.0%, respectively, of the total measured anions. Using Na as an indicator of marine origin and Al for terrestrial inputs, the proportions of sea salt and non-sea-salt elements were estimated from elemental ratios. The precipitation in this region has typical continental characteristics. The Sr concentrations varied from 0.004 to 0.885 µmol l^− 1, and strontium isotopic ratios (⁸⁷Sr/⁸⁶Sr) lay in the range of 0.71025–0.71302, with an average of 0.71143. The ⁸⁷Sr/⁸⁶Sr ratios of Lanzhou rainwater are higher than that of seawater, which reflects contributions from the radiogenic Sr sources of the aerosols. The most suitable candidate for the source would be the soil dust originating from local and distant loess and desert areas. The ⁸⁷Sr/⁸⁶Sr ratios were used to characterize different sources of base cations in rainwater, suggesting that the samples could be interpreted in terms of combinations of at least three components: soil dust derived from the Loess Plateau and desert areas in northwest China (with ⁸⁷Sr/⁸⁶Sr ~ 0.7130), seawater (with ⁸⁷Sr/⁸⁶Sr ~ 0.70917), and anthropogenic inputs (with ⁸⁷Sr/⁸⁶Sr ~ 0.7103). The high ⁸⁷Sr/⁸⁶Sr ratio and Ca and Sr content in the rainwater from Lanzhou can be attributed to the dissolution of calcium carbonate in soil dust.     

Cloud condensation nuclei measurements at Mace Head, Ireland, over the period 1994–2002

Analyses of cloud condensation nuclei (CCN) number concentrations (cm^− 3) measured at the Mace Head Atmospheric Research Station, near Carna, County Galway, Ireland, using a DH Associates Model M1 static thermal diffusion cloud chamber over the period from March 1994 to September 2002 are presented in this work. Air masses are defined as being ‘marine’ if they originate from a wind direction of 180–300° and ‘continental’ air masses are defined as originating from a wind direction of 45–135°. Air masses without such filtering were classified as ‘undefined’ air masses. Air masses were found to be dominated by marine sector air, re-affirming Mace Head as a baseline atmospheric research station. CCN levels for specific air masses at Mace Head were found to be comparable with earlier studies both at Mace Head and elsewhere. Monthly averaged clean marine (wind direction of 180–300° and black carbon absorption coefficient < 1.425 Mm^− 1) CCN and marine CCN varied between 15–247 cm^− 3 and 54–670 cm^− 3, respectively. As expected, significant increases in number concentration were found in continentally sourced CCN over that of marine CCN and were found to follow a log-normal distribution significantly tighter than that of clean marine air masses. No significant trend was found for CCN over the 9-year period. While polluted continental air masses showed a slight increase in CCN concentrations over the winter months, most likely due to increased fuel usage and a lower mixed boundary layer, the dominance of marine sector air arriving at Mace Head, which generally consists of background CCN concentrations, reduced seasonal differences for polluted air. Marine air showed a distinct seasonal pattern, with elevated values occurring over the spring and summer seasons. This is thought to be due to enhanced biogenic aerosol production as a result of phytoplankton bloom activity in the North Atlantic.     

Ambient air measurements of six bifunctional carbonyls in a suburban area

Low-molecular-weight carbonyl compounds, generated by photochemical reactions in the atmosphere and found in the exhaust of motor vehicles, have recently come to the attention of researchers because some of them are suspected carcinogens or mutagens. Six bifunctional carbonyl compounds were detected and measured in a suburban site 30 km northwest of the Tokyo metropolitan area. Samples were taken on five sunny days between 2 August and 11 August 2003 with a low-volume denuder and three-filter tandem system using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) as a sorbent. Bifunctional carbonyls were measured by gas chromatography–mass spectrometry after two derivatization processes with PFBHA and N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA). The average total (gas plus particle) concentrations were 162.8 ng m^− 3 for pyruvic acid, 113.7 ng m^− 3 for methylglyoxal, 36.0 ng m^− 3 for glycolaldehyde and 58.6 ng m^− 3 for glyoxal.     

Observational study of surface ozone at an urban site in East China

In this study, we present the observational data of near surface ozone and some meteorological parameters during 2004, at an urban site (36°42′ N, 117°08′ E, 34.5 m a.s.l.) of Jinan, China. Hourly ozone concentrations exceeding the standard value of China, 100 ppbv, were observed for 65 h (in 23 days) from April to October, and values exceeding US NAAQS (National Ambient Air Quality Standard) for 1 h ozone, 120 ppbv, were observed for 15 h (in 7 days) from late May to early July. Ozone formation presented the phenomenon of “weekend effect”, especially in summer. Monthly variation of ozone coincided with temperature except for July and August. The low ozone levels in July and August may be due to the short sunshine duration and much rainfall during this period. Among these meteorological parameters, daily averaged ozone shows a significant correlation with temperature (r = 0.66) in the year and with relative humidity (r = − 0.75) in summer. Throughout the year, high ozone concentrations were mainly associated with the wind from 180 to 247.5°, while high ozone concentration seemed to have no obvious correlation with a given wind direction in summer. An anomalous nocturnal high ozone episode during 23–25 May 2004 was investigated. Growth fractions of ozone during the nighttime episode were 62.2% and 71.1% for 23 and 24 May, respectively. Synoptic analysis shows that favorable synoptic condition had presumably elevated the background ozone level in this region. Backward trajectory analysis shows that the increase of ozone concentration and the relatively constant high ozone concentrations during the night of May 23 might originate from the transport of ozone rich air mass above boundary layer. Transport of ozone from Yangtze Delta and East Central China might be a significant process for the high ozone level during night May 24 at Jinan.     

Visibility trends in six megacities in China 1973–2007

The particulate matter pollution has been serious in Chinese megacities due to the rapidly expanding economic and industrial developments, which has significant influences in atmospheric visibility. Visibility is a highly relevant factor indicating the level of atmospheric quality, and is inversely related to the optical extinction coefficient caused by gas and particle phases. In our study, visibility trends for six major megacities (Beijing, Chengdu, Guangzhou, Shanghai, Shenyang, and Xi'an) in China were evaluated during 1973–2007 on the basis of the National Climatic Data Center (NCDC) database using four measurement methods: the days per year of daily visibility < 10 km, the days per year of daily visibility > 19 km, the annual mean visibility, and the dry extinction coefficient. The annual and seasonal change trends of visibility for each city were analyzed by using a linear regression model. The annual mean visibilities for the six cities (Beijing, Chengdu, Guangzhou, Shanghai, Shenyang, and Xi'an) were 10.67, 8.60, 10.76, 8.59, 8.16, and 9.74 km respectively. Shenyang has experienced a significant increasing trend during the entire time series while visibilities for other five sites showed decreasing trends especially since the middle of 1990s. In the southern and midwestern regions (Chengdu, Guangzhou, Shanghai, and Xi'an), visibility was best in summer, whereas in the northern regions (Beijing and Shenyang), visibility was best in spring. Mean visibility in spring was worst at Guangzhou, while for the other five cities visibility in winter was worst, probably because of coal burning during the heating period. The general degradation of visibility in these megacities was probably due to the excess aerosol loading. Consequently, an urgent targeted reduction of aerosol pollution may be needed for the sake of better air quality in Chinese megacities.     

北京地区低空风、温度层结对大气污染物垂直分布影响初探

2001年1月5～12日,2月21日～3月1日两次在北京方庄居住小区内进行了大气污染物(二氧化硫、氮氧化物)与气象要素垂直探测,历时16天.共获取了83次(一天8次)边界层垂直温、压、湿、风连续的探空资料以及不同高度(地面、100m、500m)逐时大气污染物浓度监测数据306个.该文分析了低空风日变化规律、时空分布规律、边界层气象条件对污染物垂直分布影响等等;并对1月12日、2月27日两天高浓度污染目的天气特征、温度层结和低空风以及2月25～26日出现100m浓度值高于地面现象都进行了详细分析.观测结果对于了解和研究北京地区冬季低层空气中环境化学污染物质在空中的垂直分布情况及随时间变化规律具有重要的参考价值.     

Sounding-derived parameters associated with large hail and tornadoes in the Netherlands

A study is presented focusing on the potential value of parameters derived from radiosonde data or data from numerical atmospheric models for the forecasting of severe weather associated with convective storms. Parameters have been derived from soundings in the proximity of large hail, tornadoes (including tornadoes over water: waterspouts) and thunderstorms in the Netherlands. 66,365 radiosonde soundings from six stations in and around the Netherlands between 1 Dec. 1975 to 31 Aug. 2003 were classified as being associated or not associated with these weather phenomena using observational data from voluntary observers, the Dutch National Meteorological Institute (KNMI) and lightning data from the U.K. Met. Office. It was found that instability as measured by the Lifted Index or CAPE and 0–6 km wind shear independently have considerable skill in distinguishing environments of large hail and of non-hail-producing thunderstorms. It was also found that CAPE released below 3 km above ground level is on average high near waterspouts and weak tornadoes that mostly occur with low shear in the lowest 1 km above the Earth's surface. On the other hand, low-level shear is strong in environments of stronger (F1 and F2) tornadoes and increases with increasing F-scale. This is consistent with the notion that stretching of pre-existing vertical vorticity is the most important mechanism for the formation of weak tornadoes while the tilting of vorticity is more important with stronger tornadoes. The presented results may assist forecasters to assess the likelihood of severe hail or tornadoes.     

Characteristics of gaseous pollutants near a main traffic line in Beijing and its influencing factors

Automobile exhaust emissions are becoming increasingly serious with the drastic increase of the number of vehicles in Beijing. In order to investigate the air pollution level and characteristics in the areas near the main traffic lines in Beijing and to identify the contributions from traffic and other sources, gaseous pollutants including NOx, CO, O₃, SO₂, and meteorological parameters have been monitored at a monitoring site and a contrasting site in winter and summer in 2006. The volumes of vehicles on Beiyuan Road were recorded. The average concentrations of NO, NO₂, NOx, CO, O₃, and SO₂ at the monitoring site were 0.148 mg/m³, 0.107 mg/m³, 0.333 mg/m³, 5.110 mg/m³, 0.006 mg/m³, and 0.157 mg/m³, respectively during the sampling period in winter and 0.021 mg/m³, 0.068 mg/m³, 0.101 mg/m³, 4.170 mg/m³, 0.083 mg/m³, and 0.056 mg/m³, respectively in summer. The high concentrations of CO and O₃ reflect the influence of vehicles emission near the traffic lines evidently. The higher concentrations of CO, NO and O₃ in summer may indicate that the characteristics of traffic pollution were more pronounced in summer. Results of regression analysis showed that in winter the concentrations of SO₂ and CO were significantly positively correlated with the emission of heating boilers at night and negatively correlated with wind speed in daytime. The concentrations of NO and NOx were negatively correlated with wind speed, positively correlated with emission of heating boilers in daytime and positively correlated with traffic density at nighttime. The concentrations of NO₂ were positively correlated with the emission of heating boilers in daytime and traffic density at nighttime. In summer, the air quality at the monitoring site and the contrasting site was mainly influenced by the traffic emissions.     

北京地区不同天气条件下近地面大气电场特征

利用2004年8月—2005年11月近地面大气电场仪的观测资料, 对北京地区不同天气条件下近地面大气电场特征进行分析。结果表明:北京地区晴天近地面大气电场日变化呈双峰双谷, 谷值分别出现在北京时05:00和12:00, 峰值分别出现在07:00和23:00, 并且表现出一定的季节变化; 晴天大气电场的变化与气溶胶含量的变化有密切关系, 两者呈正相关; 晴天大气电场与绝对湿度之间也表现出很强的相关性, 在一定程度上反应了水汽对大气电场的作用; 沙尘天气下风速均达到一定强度, 近地面大气电场为负值, 并且变化剧烈, 电场强度与PM₁₀之间呈现较强的负相关, 而电场强度与风速之间没有表现出明显的相关性。     

Assessment of ambient volatile organic compounds (VOCs) near major roads in urban Nanjing, China

Volatile organic compounds (VOCs) are a major component of atmospheric pollutants in Nanjing, a large city in the east of China. Accordingly, 12-h diurnal monitoring for ten consecutive days was performed adjacent to major roads in five districts, ca.1.5 m above ground level, in April, July and October 2006, and January 2007. The most numerous species of VOCs (benzene, toluene, ethylbenzene, m/p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, tetrachloromethane, trichloroethane and tetrachloroethane) were selected as the target pollutants for this field study of atmospheric distribution. The eleven VOCs were mostly found in gas phase due to their high vapor pressures. Gas-phase concentrations ranged between 0.6 and 67.9 μg m^− 3. Simultaneously, the levels of those VOCs measured near major roads were associated slightly with their regional background level. For all these areas, as expected, the high traffic area was the highest in terms of concentration. A positive correlation was also found between the VOC levels and traffic density. Our studies also provided VOC distribution, and vertical/horizontal profiles. The results show that traffic-related exposure to VOCs in major road microenvironments is higher than elsewhere and poses a potential threat to pedestrians, commuters, and traffic-exposed workers.     

Some observations on the acidity and composition of rainwater in Sydney,Australia, during the summer of 1980–81

During the summer of 1980–81, a rudimentary form of wet-only event sampling was employed to collect a total of 294 rainwater samples at 12 sites spread across the metropolitan region of Sydney, Australia's largest city. From the samples were determined conductivity, pH, ammonium, chloride and nitrate ion concentrations as well as deposited water volume. Supplementary data consisting of city-wide averaged SO₂, NO₂, NO, and O₃ concentrations and 950 mb wind speed and direction were obtained for times coinciding with the period during which each event occurred.The pH of rainwater upwind of the city and unaffected by urban/industrial emissions was found to be usually 5, whereas the volume-weighted mean pH of all the metropolitan samples was 4.4, indicating that local emissions significantly increased rainwater acidity in the near field. Time available for conversion of precursors to acids averaged 1–2 h only.Considerable day-to-day variability in rainwater composition was observed. Factors identified as contributing to this variability included precursor gas concentration, wind speed, wind direction, amount of water deposited per event and possibly time of day. These results show that physical/meteorological factors cannot be excluded from consideration if variance in rainwater composition data is to be explained.     

On the formation and growth of atmospheric nanoparticles

In this paper we summarize recent experimental, theoretical and observational results on the formation and growth of atmospheric nanoparticles. During the last years significant progress has occurred to explain atmospheric nucleation and initial steps of the growth. Due to climatic and health effects of fine and ultrafine particles the formation and growth of new aerosol particles is of growing interest. The question “How and under which conditions does the formation of new atmospheric aerosol particles take place?” has exercised the minds of scientists since the time of John Aitken, who in the late 1880s built the first apparatus to measure the number of dust and fog particles. However, only during the last 15–20 years has the measurement technology developed to such a level that size distributions of nanometer-size particles and concentrations of gases participating in particle formation can be measured in the atmosphere. Also from a theoretical point of view atmospheric nucleation mechanisms have not been resolved: several mechanisms such as ion-induced (or ion mediated) nucleation, ternary and kinetic (barrier-less) nucleation have been suggested. In the most recent theory, the activation of existing neutral and/or ion clusters has been suggested.     

Chemical character of precipitation and related particles and trace gases in the North and South of China

Rainwater samples were collected at four sites, including Beijing and Mazhuang Town in the north of China, Shenzhen and Mangdang Mountain in the south of China. Character of atmospheric particles and gases were also measured at Mazhuang Town and Mangdang Mountain. Both of Beijing and Shenzhen are urban sites; Mazhuang Town and Mangdang Mountain are rural and remote sites respectively. The atmospheric pollution at rural plain site in the north of China was more serious than that at remote mountain site in the south of China. At Beijing, Mazhuang Town, Shenzhen and Mangdang Mountain the average pH values in rainwater were 6.02, 5.97, 4.72 and 4.81, respectively and the concentrations of total ions in rainwater were 1454, 1125, 187 and 191 μeq/l, respectively. While the acidity of the rain was higher in the south than that in the north, the rainwater in the north of China was more severely polluted than that in the south. The major acidic ion in the rainwater is SO₄^2-, and NH₄⁺ is the most important neutralizing ion in rainwater at the four sites, followed by Ca²⁺. The amounts of organic acid in precipitation were compared with other sites in the world. The ratios of organic acid to total free acid in rainwater at Mangdang Mountain was 13.8% and the influence of organic acid on acidity of rainwater at mountain site in the south of China is more important. The variation of atmospheric particles, gases and components in rainwater and cloud-fog water during special rain and cloud-fog events was discussed. The importance of washout process varied with atmospheric species. The impacts of rainfall, rain duration time and wind speed on wash-out process were estimated by regression analysis.     

Continuous scanning of the mobility and size distribution of charged clusters and nanometer particles in atmospheric air and the Balanced Scanning Mobility Analyzer BSMA

Measuring of charged nanometer particles in atmospheric air is a routine task in research on atmospheric electricity, where these particles are called the atmospheric ions. An aspiration condenser is the most popular instrument for measuring atmospheric ions. Continuous scanning of a mobility distribution is possible when the aspiration condenser is connected as an arm of a balanced bridge. Transfer function of an aspiration condenser is calculated according to the measurements of geometric dimensions, air flow rate, driving voltage, and electric current. The most complicated phase of the calibration is the estimation of the inlet loss of ions due to the Brownian deposition. The available models of ion deposition on the protective inlet screen and the inlet control electrofilter have the uncertainty of about 20%. To keep the uncertainty of measurements low the adsorption should not exceed a few tens of percent. The online conversion of the mobility distribution to the size distribution and a correct reduction of inlet losses are possible when air temperature and pressure are measured simultaneously with the mobility distribution. Two instruments called the Balanced Scanning Mobility Analyzers (BSMA) were manufactured and tested in routine atmospheric measurements. The concentration of atmospheric ions of the size of about a few nanometers is very low and a high air flow rate is required to collect enough of ion current. The air flow of 52 l/s exceeds the air flow in usual aerosol instruments by 2–3 orders of magnitude. The high flow rate reduces the time of ion passage to 60 ms and the heating of air in an analyzer to 0.2 K, which suppresses a possible transformation of ions inside the instrument. The mobility range of the BSMA of 0.032–3.2 cm² V^− 1 s^− 1 is logarithmically uniformly divided into 16 fractions. The size distribution is presented by 12 fractions in the diameter range of 0.4–7.5 nm. The measurement noise of a fraction concentration is typically about 5 cm^− 3 and the time resolution is about 10 min when measuring simultaneously both positive and negative ions in atmospheric air.     

Chemical composition of aerosols in the atmosphere of Mongolia

Presented are the results of studies of the component composition of atmospheric aerosols in Mongolia for the period of 2005?C2010. It is demonstrated that the local emissions mostly affect the composition of aerosols in industrial cities (Ulan Bator and Sükhbaatar), whereas the distant transport of pollutants and the wind regime of the area, in particular, the dust storms affect in small towns with the undeveloped industry (Baruun-Urt and Sainshand). Revealed is the dependence of the composition and concentration of suspended particles on the meteorological conditions in the research area. High concentrations of aerosols were observed on the days with strong winds and air masses transport from the deserts and industrial areas of China. Low concentrations of ions were observed during periods of calm weather and in case of the air masses transport from the territories of Russia and Kazakhstan.     

库尔勒市历年沙尘天气发生特性分析

本文根据1971~2010年库尔勒市气象实测资料,分析了库尔勒市沙尘天气40年变化特征,以及沙尘天气与平均风速,降水量,平均相对湿度,平均地面0cm温度和平均气温等气象因子之间的关系。结果表明:沙尘暴、扬沙、浮尘等沙尘天气在年际、季节与各月变化上具有一致性。20世纪的70年代沙尘天气发生日数最多,从1971~2005年沙尘天气发生日数呈波动下降趋势,1971年最高,共出现沙尘天气112d但不同沙尘天气发生日数最值出现的年份不同,2005~2010年沙尘天气发生日数又开始回升,到2010年沙尘天气的发生次数已接近70年代的平均水平。其次,沙尘天气呈现春夏季节发生日数多,秋冬发生日数少的季节变化趋势,每年的4月沙尘天气出现最多,1月沙尘天气出现最少。沙尘天气的发生与空气相对湿度、降水量呈现极显著的负相关,与风速呈现极显著的正相关,而与气温的变化关系不明显。根据2010年4月的沙尘颗粒物监测表明,沙尘天气使大气中的Ca、Mg、Fe等地壳元素含量增加。