This table represents air quality in selected cities during the life of this blog. AQI stands for Air Quality Index.  Unhealthy 1 is defined as unhealthy for sensitive groups.  Unhealthy2 is unhealthy for all.

23 March 2016

St. Louis – Good – 36 AQI

Los Angeles – Moderate – 53 AQI

New York – Moderate – 54 AQI

Beijing – Good – 38 AQI

Shanghai – Moderate -70 AQI

Delhi – Hazardous – 357 AQI

10 March 2016

St. Louis – Good – 38 AQI

Los Angeles – Moderate – 77 AQI

New York – Moderate – 78 AQI

Beijing – Good – 50 AQI

Shanghai – Moderate -70 AQI

Delhi – Hazardous – 281 AQI

4 March 2016

St. Louis – Moderate – 78 AQI

Los Angeles – Moderate – 73 AQI

New York – Good – 42 AQI

Beijing – Hazardous – 330 AQI

Shanghai – Moderate -80 AQI

Delhi – Hazardous – 320 AQI

24 February 2016

St. Louis – Good – 38 AQI

Los Angeles – Good – 35 AQI

New York – Good – 44 AQI

Beijing – Moderate – 55 AQI

Shanghai – Moderate -76 AQI

Delhi – Hazardous – 442 AQI

17 February 2016

St. Louis – Good – 50 AQI

Los Angeles – Moderate- 64 AQI

New York – Good – 43 AQI

Beijing – Moderate – 59 AQI

Shanghai – Unhealthy2 – 155 AQI

Delhi – Hazardous – 249 AQI

10 February 2016

St. Louis – Good – 36 AQI

Los Angeles – Moderate- 52 AQI

New York – Good – 38 AQI

Beijing – Unhealthy2 – 236 AQI

Shanghai – Moderate – 82 AQI

Delhi – Unhealthy2 – 285 AQI

4 February 2016

St. Louis – Moderate – 54 AQI

Los Angeles – Moderate- 62 AQI

New York – Moderate – 58 AQI

Beijing – Moderate – 61 AQI

Shanghai – Unhealthy1 – 122 AQI

Delhi – Unhealthy2 – 486 AQI

27 January 2016

St. Louis – Good – 40 AQI

Los Angeles – Moderate- 61 AQI

New York – Moderate – 60 AQI

Beijing – Unhealthy2 – 234 AQI

Shanghai – Moderate – 74 AQI

Delhi – Unhealthy2 – 321  AQI

22 January 2016

St. Louis – Moderate – 82 AQI

Los Angeles – Moderate- 60 AQI

New York – Good – 33 AQI

Beijing – Good – 33 AQI

Shanghai – Unhealthy1 – 119 AQI

Delhi – Unhealthy2 – 400 AQI

15 January 2016

St. Louis – Moderate – 58 AQI

Los Angeles – Moderate- 79 AQI

New York – Moderate – 60 AQI

Beijing – Unhealthy1 – 171 AQI

Shanghai – Unhealthy1 – 187 AQI

Delhi – Unhealthy2 – 255 AQI

30 December 2015

St. Louis – Moderate – 59 AQI

Los Angeles – Moderate- 53 AQI

New York – Moderate – 91 AQI

Beijing – Moderate – 80 AQI

Shanghai – Unhealthy2 – 223 AQI

Delhi – Unhealthy2 – 999  AQI

23 December 2015

St. Louis – Moderate – 56 AQI

Los Angeles – Moderate- 59 AQI

New York – Moderate – 52 AQI

Beijing – Unhealthy2 – 153 AQI

Shanghai – Unhealthy1 – 122 AQI

Delhi – Unhealthy2 – 592  AQI

18 December 2015

St. Louis – Moderate – 55 AQI

Los Angeles – Moderate- 70 AQI

New York – Good – 35 AQI

Beijing – Unhealthy2 – 168 AQI

Shanghai – Unhealthy1 – 144 AQI

Delhi – Unhealthy2 – 282  AQI

11 December 2015

St. Louis – Moderate – 70 AQI

Los Angeles – Moderate- 56 AQI

New York – Moderate – 67 AQI

Beijing – Unhealthy2 – 225 AQI

Shanghai – Moderate – 97 AQI

Delhi – Unhealthy2 – 682 AQI

3 December 2015

St. Louis – Good – 36 AQI

Los Angeles – Moderate- 58 AQI

New York – Good – 48 AQI

Beijing – Moderate – 55 AQI

Shanghai – Unhealthy1 – 127 AQI

Delhi – Unhealthy2 – 759 AQI

27 November 2015

St. Louis – Good – 48 AQI

Los Angeles – Good- 44 AQI

New York – Moderate- 52 AQI

Beijing – Unhealthy2- 402 AQI

Shanghai – Unhealthy1 – 137 AQI

Delhi – Unhealthy2 – 406 AQI

20 November 2015

St. Louis – Good – 49 AQI

Los Angeles – Moderate – 71 AQI

New York – Good – 29 AQI

Beijing – Moderate- 99 AQI

Shanghai – Unhealthy1 – 159 AQI

Delhi – Unhealthy2 – 999 AQI

12 November 2015

St. Louis – Good – 33 AQI

Los Angeles – Moderate – 54 AQI

New York – Good – 13 AQI

Beijing – Unhealthy2 – 283 AQI

Shanghai – Unhealthy1 – 144 AQI

Delhi – Unhealthy2 – 544 AQI

5 November 2015

St. Louis – Good – 49 AQI

Los Angeles – Moderate –  55 AQI

New York – Moderate – 74 AQI

Beijing  — Moderate – 61 AQI

Shanghai – Moderate – 99 AQI

Delhi – Unhealthy1 – 199 AQI

29 October 2015

St. Louis – Good – 32 AQI

Los Angeles – Moderate –  72 AQI

New York – Good – 29 AQI

Beijing  — Good – 29 AQI

Shanghai – Moderate – 68 AQI

Delhi – Unhealthy1 – 204 AQI

22 October 2015

St. Louis – Moderate – 62 AQI

Los Angeles – Moderate –  70 AQI

New York – Moderate – 63 AQI

Beijing  — Unhealthy1 – 102 AQI

Shanghai – Unhealthy1 – 137 AQI

Delhi – Unhealthy1 – 185 AQI

14 October 2015

St. Louis – Moderate – 63 AQI

Los Angeles – Moderate –  77 AQI

New York – Good – 13 AQI

Beijing  — Unhealthy1 – 191 AQI

Shanghai – Moderate – 91 AQI

Delhi – Unhealthy2 – 248 AQI

7 October 2015

St. Louis – Moderate – 67 AQI

Los Angeles – Moderate –  55 AQI

New York – Good – 30 AQI

Beijing  — Good – 38 AQI

Shanghai – Good – 46 AQI

Delhi – Unhealthy2 – 417 AQI

9 April 2015

St. Louis – Good – 48 AQI

Los Angeles – Moderate –  51 AQI

New York – Good – 21 AQI

Beijing  — Unhealthy2 – 282 AQI

Shanghai – NA

Delhi – Unhealthy1 – 144 AQI

7 April 2015

St. Louis – Moderate – 72 AQI

Los Angeles – Good  38 AQI

New York – Moderate- 84 AQI

Beijing  — Unhealthy1 – 149 AQI

Shanghai – Moderate – 66 AQI

Delhi – Unhealthy2 – 185 AQI

6 April 2015

St. Louis – Good – 29 AQI

Los Angeles – Good  45 AQI

New York – Moderate- 51 AQI

Beijing  — Unhealthy1 – 105 AQI

Shanghai – Unhealthy1 – 102 AQI

Delhi – Hazardous  – 314 AQI

1 April 2015

St. Louis – Moderate- 73 AQI

Los Angeles – Good  40 AQI

New York – Good- 32 AQI

Beijing  — Unhealthy1 – 122 AQI

Shanghai – Moderate  – 87 AQI

Delhi – Hazardous  – 365 AQI

26 March 2015

St. Louis – Good – 38 AQI

Los Angeles – Moderate  51 AQI

New York – Moderate – 79 AQI

Beijing  — Unhealthy2 – 158  AQI

Shanghai – Moderate  – 87 AQI

Delhi – Unhealthy2  – 183

24 March 2015

St. Louis – Moderate – 66 AQI

Los Angeles – Moderate  63 AQI

New York – Good – 33 AQI

Beijing  — Unhealthy2 – 182  AQI

Shanghai – Moderate  – 70 AQI

Delhi – Hazardous  – 549 AQI

20 March 2015

St. Louis – Good – 49 AQI

Los Angeles – Unhealthy1  133 AQI

New York – Good – 49  AQI

Beijing  — Moderate – 89  AQI

Shanghai – Unhealthy1  – 149 AQI

Delhi – Hazardous  – 242 AQI

11 March 2015

St. Louis – Moderate 99 AQI

Los Angeles – Moderate -82 AQI

New York – Moderate – 54  AQI

Beijing  — Unhealthy2 – 160  AQI

Shanghai – Unhealthy1  – 120 AQI

Delhi – Hazardous  – 894 AQI

10 March 2015

St. Louis – Moderate 69 AQI

Los Angeles – Moderate -66 AQI

New York – Moderate – 79  AQI

Beijing  — Unhealthy2 – 163  AQI

Shanghai – Moderate  – 83 AQI

Delhi – Hazardous  – 939 AQI

3 March 2015

St. Louis – Moderate 54 AQI

Los Angeles – Good  -28 AQI

New York – Good – 42  AQI

Beijing  — Good – 46  AQI

Shanghai – Moderate  – 87 AQI

Delhi – Hazardous  – 815 AQI

28 February 2015

St. Louis – Moderate 60 AQI

Los Angeles – Good  -19 AQI

New York – Moderate – 75  AQI

Beijing  — Unhealthy 2 – 186  AQI

Shanghai – Moderate  – 84 AQI

Delhi – Hazardous  – 405 AQI

24 February 2015

St. Louis – Moderate – 53 AQI

Los Angeles – Good – 30 AQI

New York – Moderate – 58 AQI

Beijing — Unhealthy 2 – 237 AQI

Shanghai – Unhealthy2 – 154 AQI

Delhi – Unhealthy2 – 256 AQI

19 February 2015

St. Louis – Good – 50 AQI

Los Angeles – Unhealthy1 – 124 AQI

New York – Moderate – 63 AQI

Beijing — Unhealthy 2 – 180 AQI

Shanghai – Moderate – 84 AQI

Delhi – Hazardous – 238 AQI

17 February 2015

St. Louis – Moderate – 62 AQI

Los Angeles – Unhealthy1 – 113 AQI

New York – Moderate – 59 AQI

Beijing — Unhealthy 1 – 127 AQI

Shanghai – Unhealthy2 – 159 AQI

Delhi – Hazardous – 349 AQI

12 February 2015

St. Louis – Good – 14 AQI

Los Angeles – Moderate – 57 AQI

New York – Moderate – 62 AQI

Beijing — Unhealthy 2 – 161 AQI

Shanghai – Moderate – 90 AQI

Delhi – Hazardous – 388 AQI

10 February 2015

St. Louis – Moderate – 95 AQI

Los Angeles – Moderate – 68 AQI

New York – Moderate – 51 AQI

Beijing — Unhealthy 2 – 186 AQI

Shanghai – Unhealthy 1 – 132 AQI

Delhi – Hazardous – 344 AQI

5 February 2015

St. Louis – Moderate – 81 AQI

Los Angeles – Unhealthy1 – 102 AQI

New York – Good – 38 AQI

Beijing — Unhealthy 1 – 144 AQI

Shanghai – Unhealthy 2 – 154 AQI

Delhi – Hazardous – 622 AQ

3 February 2015

St. Louis – Moderate – 59 AQI

Los Angeles – Moderate -59 AQI

New York – Moderate – 51 AQI

Beijing — Moderate- 63 AQI

Shanghai – Unhealthy 1 – 124 AQI

Delhi – Hazardous – 359 AQ

29 January 2015

St. Louis – Moderate – 58 AQI

Los Angeles – Good -28 AQI

New York – Moderate – 61 AQI

Beijing — Good – 46 AQI

Shanghai – Moderate – 91 AQI

Delhi – Hazardous – 526 AQ

27 January 2015

St. Louis – Good – 30 AQI

Los Angeles – Moderate -56 AQI

New York – Good – 42  AQI

Beijing  — Unhealthy 1 – 115  AQI

Shanghai – Moderate  – 61 AQI

Delhi – Hazardous  – 364  AQI

23 January 2015

St. Louis – Moderate – 65 AQI

Los Angeles – Good – 43 AQI

New York – Good – 50  AQI

Beijing  — Unhealthy 1 – 132  AQI

Shanghai – Unhealthy2  – 181 AQI

Delhi – Unhealthy2 – 195  AQI

21 January 2015

St. Louis – Good – 30 AQI

Los Angeles – Unhealthy – 167 AQI

New York – Moderate – 60  AQI

Beijing  — Moderate – 80  AQI

Shanghai – Unhealthy2  – 180 AQI

Delhi – Hazardous – 288  AQI

15 January 2015

St. Louis – Moderate – 59 AQI

Los Angeles – Moderate – 68 AQI

New York – Moderate – 52  AQI

Beijing  — Hazardous – 493  AQI

Shanghai – Unhealthy2  – 178 AQI

Delhi – Hazardous – 945  AQI

6 January 2015

St. Louis – Good – 33 AQI

Los Angeles – Moderate – 68 AQI

New York – Moderate – 59  AQI

Beijing  — Unhealthy 2 – 192  AQI

Shanghai – Moderate – 63 AQI

Delhi – Hazardous – 699  AQI

2 January 2015

St. Louis – Moderate – 58 AQI

Los Angeles – Moderate – 53 AQI

New York – Moderate – 69  AQI

Beijing  — Unhealthy 2 – 187  AQI

Shanghai – Unhealthy2 – 177 AQI

Delhi – Unhealthy 2 – 252  AQI

30 December 2014

St. Louis – Good – 41 AQI

Los Angeles – Moderate – 59 AQI

New York – Good – 36  AQI

Beijing  — Good  – 46  AQI

Shanghai – Unhealthy2 – 179AQI

Delhi – Hazardous – 845  AQI

24 December 2014

St. Louis – Good – 25 AQI

Los Angeles – Moderate – 70 AQI

New York – Good – 28  AQI

Beijing  — Moderate  – 61  AQI

Shanghai – Unhealthy2 – 256 AQI

Delhi – Hazardous – 566  AQI

22 December 2014

St. Louis – Moderate – 55 AQI

Los Angeles – Moderate – 70 AQI

New York – Moderate – 63  AQI

Beijing  — Unhealthy2  – 196  AQI

Shanghai – Unhealthy21 – 159 AQI

Delhi – Hazardous – 450  AQI

18 December 2014

St. Louis – Good  – 44 AQI

Los Angeles – Moderate – 53 AQI

New York – Good – 44  AQI

Beijing  — Hazardous  – 302  AQI

Shanghai – Unhealthy 1 – 139 AQI

Delhi – Hazardous – 495  AQI

16 December 2014

St. Louis – Good –  23 AQI

Los Angeles – Moderate – 65 AQI

New York – Moderate – 72  AQI

Beijing  — Good  – 38  AQI

Shanghai – Unhealthy 1 – 134 AQI

Delhi – Hazardous – 561  AQI

11 December 2014

St. Louis – Moderate – 61 AQI

Los Angeles – NA –  AQI

New York – Good – 40  AQI

Beijing  — Moderate  –  59  AQI

Shanghai – Unhealthy 2 – 189 AQI

Delhi – Hazardous – 492  AQI

8 December 2014

St. Louis – Moderate – 61 AQI

Los Angeles – Moderate – 53 AQI

New York – Good – 34  AQI

Beijing  — Unhealthy2  –  197  AQI

Shanghai – Unhealthy 2 – 165 AQI

Delhi – Hazardous – 738  AQI

5 December 2014

St. Louis – Good – 22 AQI

Los Angeles – Good – 42 AQI

New York – Good – 39 AQI

Beijing — Unhealthy2 – 189 AQI

Shanghai – Unhealthy 2 – 175 AQI

Delhi – Hazardous – 999 AQI

4 December 2014

St. Louis – Good – 44 AQI

Los Angeles – Good – 20 AQI

New York – Moderate – 62 AQI

Beijing — Good – 25 AQI

Shanghai – Unhealthy 2 – 181 AQI

Delhi – Hazardous – 999 AQI

2 December 2014

St. Louis – Moderate 69 AQI

Los Angeles – Good – 50 AQI

New York – Good – 44 AQI

Beijing — Unhealthy 2 – 187 AQI

Shanghai – Unhealthy 1 – 154 AQI

Delhi – Hazardous – 999 AQI

1 December 2014

St. Louis – Good – 24 AQI

Los Angeles – Moderate – 72 AQI

New York – Moderate – 65 AQI

Beijing  — Unhealthy  –  53  AQI

Shanghai – Unhealthy  – 102 AQI

Delhi – Hazardous – 875  AQI

29 November 2014

St. Louis – Good – 39 AQI

Los Angeles – Good – 40 AQI

New York – Good – 45 AQI

Beijing  — Very Unhealthy  –  292  AQI

Shanghai – Moderate  – 53 AQI

Delhi – Hazardous – 999  AQI

28 November 2014

St. Louis – Moderate 59 AQI

Los Angeles – Moderate – 57 AQI

New York – Good – 35 AQI

Beijing — Very Unhealthy – 264 AQI

Shanghai – Unhealthy – 163 AQI

Delhi – Hazardous – 719 AQI