Table 2 Sources of tropospheric NOx and their estimated contribution to Uinta Mountain lake nitrates.

From: Agriculture causes nitrate fertilization of remote alpine lakes

Source of tropospheric NO x

Contribution (Tg N per year) to tropospheric NOx

Contribution (%) to tropospheric NO x

Estimated contribution to Uinta Mountain lakes (% total nitrate)

Fossil fuels

24

40

10

Lightning

12

20

5

Soil emissions

12

20

5

Biomass burning

8

13

3

NH3 oxidation

3

5

1

Transport from stratosphere

0.4

0.7

0.2

Aircraft

0.4

0.7

0.2

Total

60

100

24

  1. AON, atmospherically oxidized nitrate; MPE, modal probability estimate.
  2. The estimated contribution of each tropospheric NOx source to Uinta Mountain lakes is calculated based on the global percentage contribution to the troposphere36 and an overall contribution of AON to Uinta Mountain lakes of 24% MPE.
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