Comparison A&D UN-233 vs A&D CN-231

— Ultrasonic. Ultrasonic nebulisers operate by vibrating a special plate to break the liquid into tiny droplets, typically around 5 microns or smaller. These small droplets easily penetrate even the narrowest bronchial passages, ensuring effective inhalation. The temperature of the "steam" aligns with the surrounding air, making the inhalation process comfortable. Ultrasonic atomization is highly efficient, providing a strong therapeutic effect with compact and nearly silent devices, even pocket-sized. However, they come with drawbacks, including a relatively high cost, limited range (nebulization element to mask distance of 10 — 15 cm), which can be inconvenient, especially with children. Additionally, some drugs are not suitable for ultrasonic spraying, as it may either be ineffective or damage the active substances.

— Compressor. This type of nebuliser provides nebulization due to the operation of the compressor, which supplies a powerful stream of air to a container with a treatment solution. This allows you to create "cold steam" like that produced by the ultrasonic models described above. However compressor units are quite heavy; pocket models are less common among this type; and during operation they create a characteristic noise, which is why they are poorly suitable for small children. On the other hand, such devices are very versatile: in most cases, they are suitable for any type of inh...aled drug, and they can also be equipped with devices for changing the particle size (see below).

— Salt. These nebulisers are specialized devices designed for inhaling "salty" air, mimicking the conditions found near the sea or in salt caves. These devices typically consist of specially shaped containers filled with healing salt, equipped with a protective filter to prevent the inhalation of salt grains. Inhaling through these nebulisers allows air to pass through the salt layer, becoming enriched with beneficial ions and micronutrients. Salt ones offer advantages such as compact size, no need for power, silent operation, and relatively low cost, with the bulk of the expense attributed to the salt filler. However, their drawback lies in their specific purpose — these devices are exclusively intended for salt inhalation and cannot be used for other substances.

— Steam. Nebulisers using the evaporation of a liquid through temperature, often known as "heat-moist", have a distinct feature: the inhaled substance is at a high temperature. This characteristic provides a unique thermal effect, but it comes with both advantages and disadvantages. Steam nebulisers offer a warmth not found in other types, yet they cannot be used when the body temperature is significantly elevated, and there is an extensive list of contraindications. Moreover, elevated temperatures can lead to the destruction of many medicinal substances, limiting the range of drugs suitable for steam inhalation. Additionally, these devices often produce larger droplets and are primarily effective for treating the upper respiratory tract.

— Stationary. Stationary nebulisers, intended for fixed use rather than portability, lack the compact size and travel-friendly convenience of pocket inhalers. These models, not constrained by strict size and power limitations, can be designed to hold a significant amount of medication, offering enhanced performance. However, their inherent purpose makes them impractical for constant carry and less convenient for travel.

— Pocket. Compact nebulisers are crafted for portability, allowing users to carry them conveniently. While not all are pocket-sized, they easily fit into handbags or school backpacks. Pocket models typically feature independent power sources or are power-free (refer to "Type — Salt"). Despite their convenience, they generally exhibit lower power and performance compared to stationary counterparts.

The nebuliser's built-in medicine reservoir volume is a crucial consideration. It's important to align this parameter with medical guidelines for the prescribed treatment. A too-small capacity may require frequent refilling, disrupting the treatment process.

Also, knowing the volume of the reservoir and the nebulization rate (see below), it is possible to estimate the operating time of the nebuliser on a single refill.

The power consumed by the compressor of the nebuliser during operation; in this case, it means not only the corresponding element of compressor models (see "Type"), but also the nebulizer in ultrasonic devices.

The performance and power consumption of the nebuliser depend on this parameter. The more powerful the compressor, the higher the possible air flow rate and, accordingly, nebulization. At the same time, powerful devices consume more power (which is especially important when powered offline, see below) and can generate quite a lot of noise.

Since not all particles have the same size, this paragraph indicates exactly the average, most common particle size when splitting in this inhaler. Accordingly, lower values allow easier and deeper penetration into the bronchi.

The nebuliser's maximum noise level during normal operation is a crucial factor for user comfort, especially in situations where loud sounds are undesirable, such as when treating children or during nighttime use. It's important to note that the relationship between decibel levels and actual perceived noise is not linear. For instance, a 3 dB increase corresponds to a doubling of noise, and a 20 dB increase equals a 100 — fold increase in noise. Comparative tables are often used to assess the actual loudness of inhalers, and here are some relevant values for modern devices:

30 dB — comparable to a whisper, the maximum permissible noise level in residential premises at night according to sanitary standards;
35 dB — talking in an undertone;
40 dB — normal speech at a distance of about 10 m;
45 dB — conversation in a normal voice;
50 dB — a conversation is slightly louder than usual, it is considered the maximum noise level that does not cause noticeable inconvenience;
55 dB — car engine;
60 dB — TV at medium volume;
65 dB — loud conversations at a distance of up to 1 m.

— Mains. Operating on a standard household network of 230 V, this option enables the creation of nebulisers with versatile power and performance. With constant voltage supply, there's no concern about battery depletion during use. However, it comes with the drawback of requiring a power outlet and limiting mobility. As a result, mains power is commonly employed in stationary nebulisers (refer to "Purpose") but is rarely found in portable models.

— Batteries. Powered by replaceable batteries of a standard size — most often AA. This self-contained power source enables nebuliser use even in remote locations, providing complete independence from civilization. While quick battery replacement is possible with a spare, it limits the creation of high-power devices. Typically used in pocket models (refer to "Purpose"), this option incurs additional costs, requiring the purchase of disposable spare cells or relatively expensive rechargeable batteries. Moreover, finding batteries can be more challenging than locating a 230 V outlet for device charging, a drawback compared to built-in batteries (see below).

— Battery. Powered by its own original battery, which may be non-removable. Like the batteries described above, this option is intended mainly for compact pocket models; at the same time, batteries can have a fairly high power and work normally even with stationary nebulisers. Their advantages...are low cost and ease of use: instead of regularly buying and changing batteries, it is enough to periodically charge the device. Among the shortcomings, it is worth noting the impossibility of quickly replacing the battery — a dead battery has to be recharged, which takes time and the availability of a source of electricity. On the other hand, the specifics of the use of most nebulisers is such that this disadvantage is not critical in most cases.

Note that there are models with combined power source — mains/batteries or mains/battery. This combination allows you to combine the advantages of both options and compensate for the shortcomings, and also makes the device as versatile as possible — for each individual case, you can choose the best power option.