Een

Numeral

  van

Adposition

  de

Determiner

  belangrijkste

Adjective

  veroorzakers

Noun

  van

Adposition

  astma

Noun

  en

Coordinating conjunction

 astma-aanvallen  is

Auxiliary

  luchtvervuiling

Noun

.

First among the causes that trigger asthma and asthma attacks is air pollution.

First among the causes that trigger asthma and asthma attacks is air pollution.