#粒子形成气态氨(NH_3美元)是一个基础,因此,倾向于接受质子。首先我们有气体酸(盐酸H_2SO_4美元,HNO_3,美元$ $),物质往往反应酸(二氧化硫,美元NO_2美元),或水滴pH值较低(因为溶解酸)在大气中。与这些酸和氨然后_comes together_接受质子酸。现在protonized氨(铵,美元NH_4 ^ + $)和deprotonized酸(如美元NO_3 ^ -美元)不再是气态,但固体(超细粒子或粒子成核模式)或溶解在水滴。水滴可以视为湿颗粒。下图显示了这个过程的氨和硝酸(由二氧化氮)。[![在这里输入图像描述][1]][1],因为这有利”其本身就具有交换质子发生在表面或水滴,这些粒子生长(见下文)。#一个模范大气粒子粒度分布如下所示(_own工作((纽曼,2016,图2.1)(http://nbn-resolving.de/urn: nbn公司禁止:德:gbv: 18 - 81508))但内容基于宋飞和Pandis(2006,图2.7,p.59)基于惠特比和坎特雷尔(1976)_)。y轴显示粒子的数量(约; please see Fig 2.2 in the linked document above for details). [![enter image description here][2]][2] The major source of the coarse particles on the right are primary emissions of particles (dust, sea salt, ...). The accumulation mode particles in the center are partly caused by primary emissions (fine sea salt, combustion processes, ...) and partly grown from smaller particles (Aitken mode or ultra-fine particles). Actually, the ultra-fine particles are grown from so called nucleation mode particles by the condensation of further atmospheric gaseous compounds. The nucleation mode is missing here (and merged with the Aitken mode). Nucleation mode particles are those particles, which are formed by ammonia and atmospheric acids. Other sources for these nucleation mode particles are gaseous organic compounds, which lump together to form particles. The latter particles are also called SOA (secondary organic aerosol). Isoprene is one of the compounds that forms SOA. # health impacts When we combine air polluted by combustion emissions ($NO_X$) with air affected by agricultural emissions, we can expect the formation of ammonium nitrate particles ($NH_4^+$ + $NO_3^-$). Ammonium nitrate can irritate the eyes, nose and lungs. As stated in a comment and to the best of my knowledge, ammonium nitrate particles are not as harmful as e.g. fine soot particles. But I am not a expert on this field. Ammonium sulfate (from $SO_2$ from combustion emissions) have been shown to have negative health impacts on the respiratory system but also on the cardiovascular system (heart etc.; if the particles are sufficiently small to pierce the lung-blood barrier). Ultra fine ammonium nitrate particles can be nuclei for condensation of further gaseous compounds -- e.g. VOC (volatile organic compounds) --, which might have harmful impacts on our respiratory system. # tl;dr Thus, we generate particles by combining ammonia with atmospheric acids. References: - Seinfeld and Pandis, 2006: _Atmospheric Chemistry and Physics: From Air Pollution to Climate Change_. - Whitby and Cantrell, 1976: _Fine particles_ in _Proc. Int. Conf. Environ. Sens. and Asses_. [1]: https://i.stack.imgur.com/2ebkv.png [2]: https://i.stack.imgur.com/U037z.png