Pollution characteristics of nitrous acid and formaldehyde during the four seasons in Shenzhen
The photolysis of nitrous acid(HONO)and formaldehyde(HCHO)is a critical source of hydroxyl(OH)radicals in the atmosphere,significantly impacting ozone generation.In order to explore the pollution characteristics of HONO and HCHO,long-term observations were conducted in Shenzhen,China,from January 2022 to September 2023.The results showed that the average concentration of HONO in Shenzhen during the observation period was highest in winter(0.71×10-9),followed by autumn(0.64×10-9),spring(0.59×10-9)and summer(0.49×10-9)and the average concentration of HCHO was highest in summer(3.79×10-9),followed by autumn(2.74×10-9),winter(2.44×10-9)and spring(2.13×10-9).The diurnal variation of HONO showed a similar trend throughout the four seasons,with daytime valleys and nighttime peaks.It was also affected by traffic emissions during the morning and evening rush hours.HCHO showed a more obvious diurnal unimodal characteristics and prominent photochemical generation characteristics.OH radical budget analysis showed that HONO photolysis was the main contributor(60％)to OH radical production in Shenzhen,and it had a significant promoting effect on the early morning photochemical reaction,particularly in winter,while HCHO played a more important role in summer and at noon.Therefore,by effectively controlling HONO and HCHO,atmospheric oxidation capacity can be reduced,which helps to control O3 pollution.
万方数据
维普
