| Title: | "Surface ozone exceedances in Melbourne, Australia are shown to be under NO(x) control, as demonstrated using formaldehyde:NO(2) and glyoxal:formaldehyde ratios" |
| Author(s): | Ryan RG; Rhodes S; Tully M; Schofield R; |
| Address: | "School of Earth Sciences, The University of Melbourne, Parkville 3010, Australia; ARC Centre of Excellence for Climate System Science, The University of New South Wales, Kensington 2052, Australia; ARC Centre of Excellence for Climate Extremes, The University of New South Wales, Kensington 2052,Australia. Electronic address: rgryan@student.unimelb.edu.au. Australian Bureau of Meteorology, 700 Collins St, Docklands, Melbourne 3208, Australia. School of Earth Sciences, The University of Melbourne, Parkville 3010, Australia; ARC Centre of Excellence for Climate System Science, The University of New South Wales, Kensington 2052, Australia; ARC Centre of Excellence for Climate Extremes, The University of New South Wales, Kensington 2052,Australia" |
| DOI: | 10.1016/j.scitotenv.2020.141460 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Two and a half years of multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of nitrogen dioxide (NO(2)), formaldehyde (HCHO) and glyoxal (CHOCHO) are presented alongside in-situ ozone (O(3)) measurements in Melbourne, Australia. Seasonal and diurnal cycles, vertical profiles and relationships with key meteorological variables are provided. NO(2) and CHOCHO were found at highest concentration for low wind speeds implying that their sources were predominantly localised and anthropogenic. HCHO showed an exponential relationship with temperature and a strong wind direction dependence from the northern and eastern sectors, and therefore most likely originated from oxidation of biogenic volatile organic compounds (VOCs) from surrounding forested and rural areas. The glyoxal:formaldehyde ratio (R(gf)), reported for the first time in Australia, was consistently high compared to values elsewhere in the world with a mean of 0.105 +/- 0.0503 and tended to increase with increasing anthropogenic influence. The HCHO:NO(2) ratio (R(fn)) was used to characterise tropospheric ozone formation conditions. A strong relationship was found between high temperature, low R(gf), high R(fn) and high ozone surface concentrations. Therefore, we propose that both R(gf) and R(fn) may be useful indicators of tropospheric ozone production regimes and concentrations. The R(fn) showed that the vast majority of high ozone production episodes occurred under NO(x)-limited conditions, suggesting that surface ozone pollution events in Melbourne could be curtailed using NO(x) emission controls" |
| Keywords: | Air quality Max-doas NO(x) Tropospheric ozone VOCs; |
| Notes: | "PubMed-not-MEDLINERyan, Robert G Rhodes, Steve Tully, Matt Schofield, Robyn eng Netherlands 2020/08/20 Sci Total Environ. 2020 Dec 20; 749:141460. doi: 10.1016/j.scitotenv.2020.141460. Epub 2020 Aug 11" |
