0 a gas that has a strong, unpleasant smell and dissolves in water. It is used in various industrial processes, and can cause air pollution.
The trade intensity variable is negative for sulphur dioxide, nitrogen oxides, and biological oxygen demand (although it is not significant for nitrogen oxides) whilst it is positive for carbon dioxide.
The positive estimate throughout provides strong evidence that more human/physical-capital-intensive countries have higher sulphur dioxide concentrations, even after we control for trade and income effects.
The highest sulphur dioxide emissions occurred in burns that included magazine waste.
Estimated turning points are also broadly similar across specifications and are slightly higher than those estimated for sulphur dioxide.
Only for sulphur dioxide does the analysis suggest that trade patterns driven by environmental regulations and/or factor endowments are determining per capita emissions.
For sulphur dioxide and nitrogen oxides we have five-yearly observations for 26 developed and developing countries, covering the period 1975 - 1990.
Numerous covariates have been introduced in the past to explain sulphur dioxide concentrations in reduced-form specifications.
As with sulphur dioxide, the results for nitrogen oxides provide evidence of a robust relationship between per capita income and emissions.
