Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

Abstract

Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 and 5.5±2.8×103 cm−3 for two traffic-related components), cooking emissions (2.6±1.9 µg m−3 and 5.5±3.3×103 cm−3) and secondary aerosols (51±41 µg m−3 and 4.2±3.0×103 cm−3), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (“traffic-ultrafine”) and a component with a mode diameter of 100 nm (“traffic-fine”). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our results show that vehicular-related emissions (14 % and 30 % for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.

Evolution of organic carbon during COVID-19 lockdown period: Possible contribution of nocturnal chemistry

“…39.97 and Lon. 116.42) ( Cai et al, 2020 ; Chu et al, 2021 ; Liu et al, 2020c ; Zhou et al, 2019 ) and the sampling site in Shijiazhuang is located at Hebei Atmospheric Super Station (HAS/SJZ, about 25 m from the ground, Lat. 38.03 and Lon.…”

“…Monitor for AeRosols and GAses in ambient air (MARGA, ADI 2080, Applikon Analytical B.V.) were used to measure water-soluble ions (Cl − , NO 3 − , SO 4 2− , NH 4 + ) in PM 2.5 in Shijiazhuang and a Time of-flight-Aerosol Chemical Speciation Monitor (ToF-ACSM) was used to measure non-refractory components (OA, Cl − , NO 3 − , SO 4 2− , NH 4 + ) in PM 2.5 in Beijing. Detailed information for ToF-ACSM has been described in previous works ( Cai et al, 2020 ; Middlebrook et al, 2012 ).…”

Atmospheric gaseous hydrochloric and hydrobromic acid in urban Beijing, China: detection, source identification and potential atmospheric impacts

“…Tropospheric halogen chemistry plays a variety of roles in perturbing the fate of chemical compositions, including ozone (O 3 ) and volatile organic compounds (VOCs) in the troposphere (Saiz-Lopez and von Glasow, 2012;Simpson et al, 2015;Artiglia et al, 2017). Halogen radicals, in particular atomic chlorine (Cl q ) and bromine (Br q ), can deplete the O 3 , react rapidly with VOCs with reaction rates of up to 2 orders of magnitude faster than those of the hydroxyl radical (OH) reaction with VOCs and accelerate the depletion of gaseous elemental mercury (Atkinson et al, 2007;Calvert and Lindberg, 2004). Significant halogen-induced O 3 reduction of about 10 % of the annually averaged tropospheric ozone column was reported over the tropical marine boundary layer (Saiz-Lopez et al, 2012).…”

Rapid mass growth and enhanced light extinction of atmospheric aerosols during the heating season haze episodes in Beijing revealed by aerosol–chemistry–radiation–boundary layer interaction

“…8). With the average level of PM 2.5 measured by TEOM and ToF-ACSM, the latter scaling minimises the boundary layer accumulation effect on our analysis, as EC originates from primary emission sources (Cao et al, 2006). As shown in Fig.…”

“…Besides RIE correction, the data also did CO + 2 /NO 3 artifact correction (Pieber et al, 2016) and collection efficiency (CE) correction. The detailed information has been introduced in Cai et al (2020). Mass concentrations of ammonium nitrate, ammonium sulfate and ammonium chloride were determined according to the method introduced by Gysel et al (2007).…”