"upper and lower levels" is grammatically correct and can be used in written English.
It can be used to describe things such as hierarchies or areas of structure that have multiple layers or tiers. For example: "Drawing from a variety of sources, we can identify key patterns across both upper and lower levels of the organization."
On both the upper and lower levels, decks run the length of the building.
Impress folks by announcing that these lakes are meromictic, which means the upper and lower levels don't mix.
The upper and lower levels create two different material environments expressive of Milstein Hall's structure and form.
In a trance – lost in the music on my headphones – I automatically made for the shopping mall which connects the upper and lower levels of the station.
Ceiling tiles have been removed on both the upper and lower levels of the station with no appearance of progress to improve the conditions.
Most airports will disembark passengers from one level, though newer airports like Hong Kong will be able to link passenger gangways at both upper and lower levels.
The bridge has an upper and lower level with signs that give the traffic wait times for both levels.
The effect of different Tm3+ concentrations on the upper and lower level lifetimes and on the emission spectrum has also been reported for designing a broadband multi-channel S-band TDFA.
In this study, the weather forecasting model of the National Centre for Medium Range Weather Forecasting (NCMRWF) is used for examining the characteristics of round-off-errors on three different computer architectures – PARAM 10K, SUNFIRE 6800 and Dec Alpha for several meteorological parameters such as precipitation, temperature at the surface and mid-atmosphere, and upper and lower level winds.
The dashed line shows the linear fit of the normal data, with solid lines representing the upper and lower level normal range given by 95% confidence levels of the mean.
To conclude the problem formulation, it is stated that the computation of upper and lower level objectives is carried out via sophisticated process simulation algorithms which numerically evaluate a series of partial differential equations governing the complex non-isothermal and reactive resin behavior in the fibrous media.
