The Ammonium Salt in PM2.5 Was Calculated As Follows

The ammonium salt in PM2.5 was calculated as follows:

The NH4+ accounted for 4.54% of the PM2.5 mass concentration. If PM2.5 was 100 grams, the weight of ammonium ion was 4.54 grams, and the molecular weight of (NH4)2SO4 was 132, then the weight of (NH4)2SO4 was calculated as {(4.54÷18)÷2}×132=16.65 (g); Finally, the calculated result was (16.65÷100)×100% = 16.65%. Ammonium salts accounted for 16.65% of the total. The results showed that, there was sufficient NH3 present to almost completely neutralize SO42- to form (NH4)2SO4.

Table Sup2 Summary of meteorological conditions and number of PM2.5samples collected during theperiod of July2013 ~August 2014.

Sampling date / Seasona / Temperature
/℃ / Relative humidity
/% / Weather / Wind direction / Windpower / Number ofPM2.5samples
daily / total
1-Jul-2013 / summer / 34℃~27℃ / 69 / cloudy / south / 3~4 / 2 / 14
2-Jul-2013 / 36℃~29℃ / 71 / cloudy / southwest / 4~5 / 2
3-Jul-2013 / 35℃~29℃ / 74 / cloudy / southwest / 4~5 / 2
4-Jul-2013 / 35℃~29℃ / 76 / cloudy / southwest / 4~5 / 2
5-Jul-2013 / 31℃~34℃ / 79 / rain / west / 3~4 / 0
6-Jul-2013 / 26℃~23℃ / 86 / rain / south / 3~4 / 0
7-Jul-2013 / 30℃~25℃ / 88 / rain / south / 3~4 / 0
8-Jul-2013 / 33℃~27℃ / 87 / cloudy / southwest / 4~5 / 2
9-Jul-2013 / 35℃~27℃ / 79 / cloudy / southwest / 4~5 / 2
10-Jul-2013 / 35℃~27℃ / 76 / sunny / southwest / 4~5 / 2
1-Aug-2013 / summer / 35℃~28℃ / 74 / rain / south / 3~4 / 0 / 14
2-Aug-2013 / 36℃~28℃ / 68 / cloudy / south / 3~4 / 2
3-Aug-2013 / 33℃~28℃ / 93 / rain / southwest / 4~5 / 0
4-Aug-2013 / 34℃~28℃ / 87 / rain / southwest / 4~5 / 0
5-Aug-2013 / 36℃~28℃ / 65 / cloudy / southwest / 4~5 / 2
6-Aug-2013 / 37℃~29℃ / 63 / cloudy / southwest / 4~5 / 2
7-Aug-2013 / 38℃~28℃ / 61 / cloudy / southwest / 4~5 / 2
8-Aug-2013 / 39℃~29℃ / 60 / sunny / southwest / 4~5 / 2
9-Aug-2013 / 39℃~29℃ / 55 / sunny / southwest / 4~5 / 2
10-Aug-2013 / 39℃~30℃ / 82 / cloudy / south / 4~5 / 2
1-Sep-2013 / summer / 29℃~19℃ / 78 / sunny / northeast / 3~4 / 2 / 14
2-Sep-2013 / 29℃~20℃ / 81 / cloudy / northeast / 3~4 / 2
3-Sep-2013 / 29℃~20℃ / 79 / cloudy / northeast / 3~4 / 2
4-Sep-2013 / 29℃~21℃ / 83 / cloudy / northeast / 3~4 / 2
5-Sep-2013 / 22℃~17℃ / 90 / rain / northeast / 3~4 / 0
6-Sep-2013 / 20℃~17℃ / 93 / rain / northeast / 3~4 / 0
7-Sep-2013 / 24℃~19℃ / 88 / rain / northeast / 3~4 / 0
8-Sep-2013 / 27℃~22℃ / 82 / cloudy / east / 3~4 / 2
9-Sep-2013 / 30℃~23℃ / 85 / cloudy / east / 3~4 / 2
10-Sep-2013 / 29℃~23℃ / 88 / rain / north / 3~4 / 0
11-Sep-2013 / 25℃~22℃ / 92 / rain / northeast / 3~4 / 0
12-Sep-2013 / 28℃~23℃ / 90 / rain / northeast / 3~4 / 0
13-Sep-2013 / 29℃~24℃ / 88 / rain / northeast / 3~4 / 0
14-Sep-2013 / 33℃~22℃ / 83 / cloudy / east / 3~4 / 2
1-Oct-2013 / autumn / 26℃~16℃ / 68 / sunny / north / 3~4 / 2 / 14
2-Oct-2013 / 26℃~14℃ / 63 / sunny / northeast / 4~5 / 2
3-Oct-2013 / 24℃~13℃ / 66 / sunny / northeast / 3~4 / 2
4-Oct-2013 / 25℃~15℃ / 68 / sunny / east / 3~4 / 2
5-Oct-2013 / 26℃~18℃ / 74 / cloudy / east / 3~4 / 2
6-Oct-2013 / 25℃~20℃ / 74 / rain / northeast / 4~5 / 0
7-Oct-2013 / 23℃~21℃ / 78 / rain / northeast / 5~6 / 0
8-Oct-2013 / 23℃~17℃ / 76 / rain / northeast / 4~5 / 0
9-Oct-2013 / 25℃~16℃ / 73 / cloudy / east / 3~4 / 2
10-Oct-2013 / 28℃~17℃ / 71 / sunny / south / 3~4 / 2
1-Nov-2013 / autumn / 20℃~15℃ / 70 / cloudy / east / 3~4 / 2 / 14
2-Nov-2013 / 20℃~15℃ / 82 / rain / northeast / 3~4 / 0
3-Nov-2013 / 20℃~12℃ / 62 / cloudy / north / 4~5 / 2
4-Nov-2013 / 20℃~10℃ / 66 / cloudy / northeast / 3~4 / 2
5-Nov-2013 / 20℃~12℃ / 73 / cloudy / southeast / 3~4 / 2
6-Nov-2013 / 20℃~10℃ / 69 / cloudy / west / 3~4 / 2
7-Nov-2013 / 23℃~12℃ / 54 / sunny / southwest / 1~2 / 2
8-Nov-2013 / 24℃~15℃ / 78 / cloudy / east / 3~4 / 2
1-Dec-2013 / winter / 13℃~2℃ / 57 / sunny / northwest / 3~4 / 2 / 14
2-Dec-2013 / 15℃~2℃ / 54 / sunny / south / 3~4 / 2
3-Dec-2013 / 17℃~5℃ / 69 / cloudy / south / 1~2 / 2
4-Dec-2013 / 16℃~6℃ / 55 / sunny / east / 1~2 / 2
5-Dec-2013 / 17℃~5℃ / 69 / cloudy / northwest / 3~4 / 2
6-Dec-2013 / 13℃~4℃ / 66 / cloudy / north / 3~4 / 2
7-Dec-2013 / 15℃~5℃ / 63 / cloudy / southeast / 1~2 / 2
1-Jan-2014 / winter / 16℃~2℃ / 45 / sunny / west / 3~4 / 2 / 14
2-Jan-2014 / 17℃~2℃ / 54 / sunny / east / 3~4 / 2
3-Jan-2014 / 16℃~2℃ / 58 / cloudy / northwest / 4~5 / 2
4-Jan-2014 / 10℃~ -1℃ / 50 / sunny / north / 3~4 / 2
5-Jan-2014 / 12℃~1℃ / 57 / cloudy / southeast / 3~4 / 2
6-Jan-2014 / 13℃~7℃ / 58 / cloudy / east / 4~5 / 2
7-Jan-2014 / 9℃~6℃ / 63 / rain / northeast / 3~4 / 0
8-Jan-2014 / 7℃~ -2℃ / 61 / rain / west / 5~6 / 0
9-Jan-2014 / 6℃~ -3℃ / 51 / sunny / east / 3~4 / 2
1-Feb-2014 / winter / 22℃~10℃ / 49 / cloudy / west / 3~4 / 2 / 14
2-Feb-2014 / 20℃~6℃ / 91 / rain / east / 3~4 / 0
3-Feb-2014 / 9℃~ -1℃ / 82 / rain / northeast / 4~5 / 0
4-Feb-2014 / 6℃~0℃ / 54 / cloudy / northeast / 4~5 / 2
5-Feb-2014 / 4℃~1℃ / 80 / snowy / east / 4~5 / 2
6-Feb-2014 / 5℃~1℃ / 93 / rain / northeast / 4~5 / 0
7-Feb-2014 / 2℃~ -3℃ / 92 / snowy / west / 4~5 / 2
8-Feb-2014 / 4℃~ -1℃ / 76 / cloudy / west / 3~4 / 2
9-Feb-2014 / 2℃~ -5℃ / 70 / cloudy / northeast / 4~5 / 2
10-Feb-2014 / 1℃~ -4℃ / 63 / cloudy / north / 3~4 / 2
1-Mar-2014 / winter / 8℃~2℃ / 87 / rain / northeast / 3~4 / 0 / 14
2-Mar-2014 / 11℃~4℃ / 60 / cloudy / east / 3~4 / 2
3-Mar-2014 / 13℃~5℃ / 68 / cloudy / east / 4~5 / 2
4-Mar-2014 / 11℃~4℃ / 80 / cloudy / east / 3~4 / 2
5-Mar-2014 / 12℃~4℃ / 62 / cloudy / northeast / 4~5 / 2
6-Mar-2014 / 7℃~1℃ / 67 / rain / east / 4~5 / 0
7-Mar-2014 / 11℃~3℃ / 66 / cloudy / east / 3~4 / 2
8-Mar-2014 / 7℃~0℃ / 71 / rain / east / 4~5 / 0
9-Mar-2014 / 14℃~3℃ / 67 / sunny / southeast / 3~4 / 2
10-Mar-2014 / 14℃~5℃ / 57 / sunny / southeast / 4~5 / 2
1-Apr-2014 / spring / 20℃~10℃ / 71 / cloudy / east / 3~4 / 2 / 14
2-Apr-2014 / 21℃~11℃ / 67 / cloudy / east / 3~4 / 2
3-Apr-2014 / 21℃~7℃ / 63 / cloudy / northeast / 4~5 / 2
4-Apr-2014 / 20℃~9℃ / 44 / sunny / southwest / 3~4 / 2
5-Apr-2014 / 19℃~6℃ / 50 / sunny / northeast / 4~5 / 2
6-Apr-2014 / 18℃~9℃ / 42 / cloudy / east / 3~4 / 2
7-Apr-2014 / 20℃~12℃ / 59 / cloudy / southeast / 3~4 / 2
1-May-2014 / spring / 28℃~16℃ / 57 / sunny / south / 3~4 / 2 / 14
2-May-2014 / 26℃~14℃ / 51 / cloudy / north / 4~5 / 2
3-May-2014 / 24℃~15℃ / 56 / cloudy / east / 3~4 / 2
4-May-2014 / 21℃~10℃ / 73 / cloudy / northwest / 4~5 / 2
5-May-2014 / 22℃~11℃ / 47 / sunny / southeast / 3~4 / 2
6-May-2014 / 24℃~13℃ / 45 / sunny / southeast / 3~4 / 2
7-May-2014 / 28℃~16℃ / 51 / sunny / southwest / 4~5 / 2
1-Jun-2014 / summer / 26℃~21℃ / 90 / sunny / southeast / 5~6 / 2 / 14
2-Jun-2014 / 25℃~19℃ / 81 / rain / northwest / 5~6 / 0
3-Jun-2014 / 25℃~19℃ / 70 / cloudy / northwest / 4~5 / 2
4-Jun-2014 / 28℃~19℃ / 66 / cloudy / northwest / 3~4 / 2
5-Jun-2014 / 30℃~21℃ / 72 / cloudy / east / 3~4 / 2
6-Jun-2014 / 31℃~22℃ / 63 / cloudy / southeast / 3~4 / 2
7-Jun-2014 / 32℃~22℃ / 68 / cloudy / southeast / 3~4 / 2
8-Jun-2014 / 32℃~21℃ / 68 / cloudy / east / 3~4 / 2
1-Jul-2014 / summer / 26℃~22℃ / 91 / rain / southeast / 3~4 / 0 / 14
2-Jul-2014 / 26℃~21℃ / 99 / rain / west / 3~4 / 0
3-Jul-2014 / 30℃~22℃ / 80 / cloudy / east / 3~4 / 2
4-Jul-2014 / 26℃~21℃ / 90 / rain / east / 3~4 / 0
5-Jul-2014 / 23℃~21℃ / 96 / rain / north / 4~5 / 0
6-Jul-2014 / 29℃~21℃ / 81 / cloudy / northwest / 3~4 / 2
7-Jul-2014 / 30℃~21℃ / 79 / cloudy / northeast / 3~4 / 2
8-Jul-2014 / 30℃~23℃ / 79 / cloudy / east / 3~4 / 2
9-Jul-2014 / 31℃~24℃ / 82 / cloudy / west / 4~5 / 2
10-Jul-2014 / 33℃~25℃ / 71 / cloudy / west / 3~4 / 2
11-Jul-2014 / 34℃~25℃ / 73 / rain / west / 3~4 / 0
12-Jul-2014 / 28℃~22℃ / 94 / rain / north / 3~4 / 0
13-Jul-2014 / 29℃~23℃ / 85 / cloudy / southwest / 3~4 / 2
1-Aug-2014 / summer / 29℃~25℃ / 88 / rain / northeast / 4~5 / 0 / 14
2-Aug-2014 / 30℃~26℃ / 81 / rain / west / 4~5 / 0
3-Aug-2014 / 34℃~26℃ / 75 / cloudy / northwest / 3~4 / 2
4-Aug-2014 / 36℃~27℃ / 71 / cloudy / southeast / 3~4 / 2
5-Aug-2014 / 36℃~27℃ / 73 / cloudy / southeast / 3~4 / 2
6-Aug-2014 / 34℃~27℃ / 82 / rain / east / 3~4 / 0
7-Aug-2014 / 31℃~25℃ / 93 / rain / west / 3~4 / 0
8-Aug-2014 / 28℃~24℃ / 96 / rain / west / 3~4 / 0
9-Aug-2014 / 27℃~23℃ / 95 / rain / west / 3~4 / 0
10-Aug-2014 / 27℃~23℃ / 86 / cloudy / west / 3~4 / 2
11-Aug-2014 / 28℃~23℃ / 83 / cloudy / northeast / 3~4 / 2
12-Aug-2014 / 27℃~22℃ / 79 / rain / east / 3~4 / 0
13-Aug-2014 / 24℃~21℃ / 94 / rain / northeast / 4~5 / 0
14-Aug-2014 / 24℃~21℃ / 96 / rain / north / 3~4 / 0
15-Aug-2014 / 29℃~22℃ / 85 / cloudy / north / 3~4 / 2
16-Aug-2014 / 28℃~22℃ / 89 / rain / east / 3~4 / 0
17-Aug-2014 / 25℃~21℃ / 91 / cloudy / northeast / 3~4 / 2
Total / 196

a In Nanjing, based on local climate, the seasons were defined as follows: spring (March 24 – May 25), summer (May 26 – September 18), autumn (September 19 – November 20) and winter (November 21 – March 23).